As a wireless communication scheme which can be employed in a communication system, various communication schemes such as a personal handy phone system (PHS) or a long term evolution (LTE) are known. With progress of the wireless communication scheme, mobile stations supporting the various wireless communication schemes are provided. Specifically, there is provided a mobile station that can access both of the PHS, which is supplied from a long time ago and thus has a wide coverage area, and the LTE, which can carry out a high-speed communication but has a limited coverage area.
Generally, when various wireless communication schemes can be employed in a communication system, a mobile station uses a higher speed communication scheme. This is because a scheme having a higher data transmission speed can smoothly supply more diverse services.
However, a new high-speed wireless communication scheme has a tendency of increasing power consumption sometimes. The reasons are as follows. The first reason is that it is necessary to increase an output of a radio wave so as to reduce errors even in a multi-level modulation. The second reason is that an output of an amplifier in a mobile station is increased in a case of an out-of-range area or a weak radio wave. The third reason is that, since a coverage area is narrow, and power consumption for cell search is increased in a waiting state.
In this regard, Patent Literatures 1 and 2 disclose techniques in which a mobile station supporting various wireless communication schemes having different power consumptions switches the employed wireless communication scheme depending on the residual capacity of a battery.